Face processing impairments after amygdalotomy.

We report an investigation of face processing impairments in D.R., a 51-year-old woman with a partial bilateral amygdalotomy.

Handedness and longevity: archival study of cricketers.

Objective: To test whether handedness is associated with a change in longevity.

Design: Archival survey.

Setting: British Isles.

Lack of effect of lesions in the anterior cingulate cortex and retrosplenial cortex on certain tests of spatial memory in the rat.

The effects of cytotoxic lesions in either the anterior cingulate cortex or the retrosplenial cortex were compared with those of fornix lesions on three tests of spatial memory. Two of the tasks, delayed nonmatching-to-position and spatial reversal learning, were tested in an automated apparatus. The third task, forced alternation, was tested in a T-maze.

The ability of amnesic subjects to estimate time intervals.

Amnesic subjects suffering from Korsakoff's syndrome and post-viral encephalitis were assessed on their ability to estimate short temporal durations using two quite different tasks. In the first experiment subjects were required to reproduce and estimate intervals of between 3 and 96 sec. In the second experiment subjects carried out an automated Fixed Interval task using intervals of 15 and 30 sec.

The effects of lesions to the fornix and dorsomedial thalamus on concurrent discrimination learning by rats.

Rats with lesions in either the fornix or the thalamic nucleus medialis dorsalis were unimpaired on the acquisition of two object discrimination tasks. The same animals were then tested on a concurrent learning task in which various object discriminations were presented at different rates during the same session. This arrangement was primarily designed to minimise any response bias effects.

The failure of context shifts to alter the recognition of faces: implications for contextual deficits in amnesia.

The effects of contextual changes were examined in a group of divers performing a test of face recognition. No evidence was found that the shift from above to below water, or vice versa, disrupted recognition. The fact that the same test of visual recognition is sensitive to amnesic subjects poses a challenge to certain versions of the contextual deficit theory of amnesia.

Spontaneous recognition of object configurations in rats: effects of fornix lesions.

The effects of fornix lesions were examined in an object recognition memory test based on spontaneous exploration. In the standard condition an object (A) was presented in the sample phase and then presented again in the test phase alongside a new object (B). Both fornix-transected (Fx) and control (Co) rats spent more time exploring the new object than the familiar object after retention delays of 1 min and 15 min.

The contribution of the anterior thalamic nuclei to anterograde amnesia.

This paper first reviews the anatomical, pathological, and neuropsychological evidence implicating the anterior thalamic nuclei in memory processes. It is concluded that there is much indirect evidence indicating that anterior thalamic dysfunction is an important factor in anterograde amnesia. More direct evidence for the involvement of the anterior thalamic nuclei in memory processes emerges from two experiments with rats that examined performance of a spatial test of working memory, delayed nonmatching-to-position.

The contribution of the amygdala to normal and abnormal emotional states.

Lesion studies in monkeys have provided some of the most compelling evidence for the involvement of the amygdala in emotional and social behaviour. In spite of this it has proved surprisingly difficult to uncover the precise nature of the role of the amygdala. A number of recent studies now indicate that the amygdala is involved in a specific class of stimulus-reward associations and this discovery, combined with important anatomical findings, has made it possible to gain a much more detailed appreciation of the contribution of the amygdala to emotion in non-human primates.

Evidence for longevity differences between left handed and right handed men: an archival study of cricketers.

Study Objective: The aim was to examine the relationship between handedness and longevity.

Design: This was an archival (retrospective) survey of a cohort of adult men who had played 'first-class cricket'.

Setting: The United Kingdom

Participants: The subjects consisted of all of the deceased players included in an encyclopedia of 'first-class cricket' whose bowling hand had been recorded (n = 3165).

Lack of effect of dorsomedial thalamic lesions on automated tests of spatial memory in the rat.

The effects of cytotoxic lesions of nucleus medialis dorsalis on tests of spatial memory were examined in the rat. Extensive lesions of the nucleus did not impair either the acquisition or the subsequent performance of an automated test of working memory, delayed nonmatching-to-position. Detailed analysis of the animals' performance over varying retention delays failed to reveal any evidence of a deficit.

The effects of fornix and medial prefrontal lesions on delayed non-matching-to-sample by rats.

The present study compared the effects of fornix lesions and medial prefrontal lesions on a test of object recognition memory, delayed non-matching-to-sample. Neither lesion impaired the acquisition of this non-spatial test of working memory, indeed there was clear evidence that fornix damage resulted in improved non-matching performance during initial acquisition. This improvement in performance could be related to the loss of a spatial bias during the early stages of training.

Removal of the hippocampus and transection of the fornix produce comparable deficits on delayed non-matching to position by rats.

Rats with radiofrequency lesions of the fimbria/fornix or with extensive aspiration lesions of the hippocampal region (the hippocampus proper, dentate gyrus, and subicular complex) were tested on their performance of a delayed non-matching to position task which had been learnt before surgery. On a given trial, one of two sample levers was presented in a random manner. Following a response on this lever and a subsequent delay, both levers were presented and reward was now contingent on a response on the lever that was not used as the sample.

The performance of postencephalitic amnesic subjects on two behavioural tests of memory: concurrent discrimination learning and delayed matching-to-sample.

The performance of a group of three postencephalitic subjects with anterograde amnesia was examined on a series of concurrent visual discrimination problems and on a test of visual recognition, delayed matching-to-sample. These tests were chosen as they have been used to assess experimental models of anterograde amnesia in nonhuman primates. In comparison with a group of normal subjects the postencephalitic group were impaired on the more difficult concurrent discrimination problems.

Lesions of the fornix but not the amygdala impair the acquisition of concurrent discriminations by rats.

Rats with lesions in either the fornix, the amygdala, or both were compared with control animals on the acquisition of three different concurrent object discrimination tasks. In the first task the animals received one trial per day on each of six pairs of stimulus objects ('spaced' condition). In the second task the animals received four trials per day on each of six stimulus pairs ('standard' condition), and in the last task the animals received 36 trials on each of two stimulus pairs in just a single day ('massed' condition).

Occupation and handedness: an examination of architects and mail survey biases.

Handedness among architects was determined by mail survey. Contrary to previous reports, no evidence was found of an excess of left-handers among a sample of 236 fully qualified male architects and 78 male architectural students. A second study examined whether the use of mail surveys systematically biases the returns of handedness questionnaires.

Both fornix and anterior thalamic, but not mammillary, lesions disrupt delayed non-matching-to-position memory in rats.

Rats with radiofrequency lesions of the fimbria/fornix, or neurotoxic lesions of the mammillary bodies or the anterior thalamic nuclei were tested on their ability to perform a delayed non-matching-to-position task that had been learnt before surgery. In this task rats had to respond to a sample lever in an operant chamber and, after a variable delay (during which they were required to respond at the magazine tray), press the other lever when both were presented. Extensive mammillary body lesions had no effect on performance.

Medial dorsal thalamic lesions and working memory in the rat.

Pigmented rats of the DA strain with either radiofrequency or ibotenic acid lesions of the thalamic nucleus medialis dorsalis were postoperatively given nonspatial and spatial tests of working memory. In the nonspatial task, delayed nonmatching-to-sample, rats with both types of thalamic lesions showed acquisition impairments. The subgroup of rats with nucleus medialis dorsalis lesions that were able to reach the acquisition criterion did, however, perform normally when the retention interval was extended to 60 s.

Amygdaloid lesions and stimulus-reward associations in the rat.

Rats with amygdaloid lesions were trained on learning set tasks designed to tax stimulus-reward associations. Lesions centred in the medial and ventral half of the amygdala had no effect on the acquisition of two object discriminations but did impair successive reversals of the second discrimination. The same lesions had no effect, however, on the acquisition of a spatial win-stay lose-shift task which taxed one-trial place-reward associations.

Transient impairment of recognition memory following ibotenic-acid lesions of the basal forebrain in macaques.

To assess the contributions of the basal forebrain cholinergic nuclei to visual recognition memory in macaques, we compared the effects of lesions of (a) the nucleus basalis of Meynert, (b) the medial septal and diagonal band nuclei, and (c) all nuclei combined on performance of delayed nonmatching-to-sample with trial-unique stimuli. Whereas monkeys with the separate lesions did not differ from each other or from normal control animals, those with combined lesions showed a significant impairment. With time and extended practice, however, the performance of the animals with combined lesions recovered to normal levels.

The effects of mammillary body and combined amygdalar-fornix lesions on tests of delayed non-matching-to-sample in the rat.

A series of experiments compared the effects of mammillary body lesions with those of combined damage to the amygdala and fornix on 2 tests of working memory, both of which used the delayed non-matching-to-sample rule. This comparison was based on evidence of the involvement of these regions in anterograde amnesic syndromes. The mammillary body lesions had no effect on the acquisition or subsequent performance of a non-spatial recognition task and had only a mild effect on the acquisition of a spatial forced-alternation task.

Concurrent and sequential pattern discrimination learning by patients with Korsakoff amnesia.

Patients with Korsakoff's syndrome and alcoholic controls learned to discriminate sets of pairs of patterns presented concurrently, in order to test predictions based on monkeys' performance in similar tasks following medial temporal or diencephalic lesions. In Experiment 1 the subjects learned a 2-pair, a 6-pair and a 10-pair set; the Korsakoff group were impaired on the first and last, but not on the second set. In Experiment 2, the same subjects learned single pairs sequentially, and 2-pair and 8-pair sets concurrently.

Visual impairments in macaques following inferior temporal lesions are exacerbated selectively by additional damage to superior temporal sulcus.

The present study examined the behavioural effects of removing the inferior temporal cortex (area TE) either on its own or in combination with the adjacent fundus and upper bank of the superior temporal sulcus (area STP). Comparisons with preoperative behaviour showed that the addition of superior temporal sulcal damage led to an increase in visual components of the Klüver-Bucy syndrome, i.e.

Cross-modal matching by amnesic subjects.

The present study examined the performance of two groups of amnesic subjects on a cross-modal identification task. It was found that subjects with Korsakoff's disease did not differ from alcoholic controls on their ability to match the tactile feel of an arc with the visual appearance of the full circle from which the arc was taken. The postencephalitic subjects were, however, impaired on this same task.

Working memory in aged rats.

The performances of young and aged rats were compared on a spatial (spatial delayed nonmatching-to-sample) and a nonspatial (object delayed nonmatching-to-sample) test of working memory. Although evidence was found that aging showed acquisition of both of these tasks, performance over different retention intervals of up to 60 s was normal once the task was mastered. An impairment was found, however, in the performance of the spatial test when the number of locations to be remembered on each trial was increased from one to two.